Contribution of Padova Team to SSA - NEO Segment : the SINEO project Monica Lazzarin

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1 Contribution of Padova Team to SSA - NEO Segment : the SINEO project Monica Lazzarin The contribution of Padova Team to SSA activities mainly focuses on the NEO segment, in particular the investigation of the surface composition of NEO and related issues. Padova Team is involved in the European Space Situational Awareness (SSA) programme, Near Earth Object segment, responsible Detlef Koschny of the European Space Agency ( and in the project approved by ESA Enabling Technologies for SSA-NEO segment Telespazio-INAF-Univ. of Pisa proposers.

2 Involved Researchers Padova Team is composed by researchers of the Department of Physics and Astronomy of Padova University. Monica Lazzarin - Dip. di Fisica e Astronomia - Univ. di Padova - Ricercatore monica.lazzarin@unipd.it Sara Magrin- Dip. di Fisica e Astronomia - Univ. di Padova Assegnista sara.magrin.1@unipd.it Ivano Bertini - Dip. di Fisica e Astronomia - Univ. di Padova - Assegnista Ivano.bertini@unipd.it Fiorangela La Forgia - Dip. di Fisica e Astronomia - Univ. di Padova PhD fiorangela.laforgia@unipd.it Maurizio Pajola - Dip. di Fisica e Astronomia - Univ. di Padova PhD maurizio.pajola@unipd.it

3 Field of interest in SSA: Near Earth Objects segment The Team isexpert in the studyofthe physicalpropertiesofsmall bodies, asteroids and comets, from groudbased and space instrumentation. Amongthe severalactivitiesin thisfield: Started some years ago a long term spectroscopic survey of Near Earth Objects (SINEO=Spectroscopic Investigation of Near Earth Objects) to investigate their surface composition, important physical parameter also for mitigation purposes All members involved as Co-I or Associate Scientists in the space mission Rosetta (OSIRIS camera); developed algorithms to analyze the images taken by the OSIRIS camera of the two encountered asteroids: Steins and Lutetia. Mostofthe Team members involved in the sample return Marco Polo-R mission for the study of a Near Earth Asteroid. Mostofthe Team members partecipate to the ESA SSA-Near Earth Objects, PI Koschny and to the Enabling Technologies for SSA awareness-neo segment project by Telespazio-INAF-Univ.Pisa

4 Motivations for NEO investigation: Comets Where do NEOs originate? Asteroids Kuiper Belt Oort Cloud Collision with the Sun ~20% Near-Earth Space T~ My Collision with E/V/M ~80% Main Belt: 3:1, 5:2, 2:1, 6... Hyperbolic orbits Why NEO spectroscopy? Surface composition and mineralogy relationships with comets, MBOs and meteorites - NEOs origin - Solar System formation - Solar System dynamic - Solar System evolution - PHA investigation

5 Funded projects on NEOs physical investigation: ITANET project 1995, CNR, Search and study of potential hazardous objects for the Earth (NEOs) (Astronomy Dept. of Padova, Obs. of Torino, Brera, Catania, Roma, Univ. of Pisa. PI: A. Carusi). PRIN-MIUR 2004 project, University Minister, Physical and dynamical study of Near Earth Objects (Astronomy Dept. of Padova, Obs. of Torino, Catania, Brera, Roma, Univ. of Pisa. PI: A. Milani). National contract funded by ASI ''Studies of Solar System exploration', PI: Angioletta Coradini. Local program on NEOs. PRIN-INAF 2009 project, INAF, Physical and dynamical study of NEOs (Astronomy Dept. of Padova, Obs. of Torino and Roma, Univ. of Pisa and IASF- Roma PI:G.Valsecchi). SSA-Telespazio-INAF-Univ. of Pisa project approved by ESA 2010 Enabling Technologies for SSA awareness-neo segment

6 Previous experience and obtained results Long timeexperienceon spectroscopicinvestigationofasteroids, comets, Trans Neptunianobjects, transitionobjects. Facilityused: ESO-CileTelescopes(NTT, VLT), Mauna KeaTelescopes(CFHT, IRTF), TNG-La Palma-Canarias. SINEO project (Spectroscopic Investigation of Near Earth Objects): one of the largest spectroscopic data base with about 200 spectra of NEOs in the visible and Near Infrared region ( micron) partly published and not yet completely analyzed. 150 spectra in the visible and 90 in the NIR. Some examples: C S

7 Taxonomic classification: needed for estimate the composition of the objects. Obtained almost all the taxonomic classes found in the MB that confirms NEOsvariegate origin. The use of the Principal Component Analysis confirms the taxonomic classification obtained. C- X- S- PCA:performed using SMASS II data (Binzel 2002). Our data distribute in the same clusters defined by SMASS II data.

8 Comparison of NEO spectra with those of about 900 meteorites taken from RELAB catalog. Most meteroriteshas not a clear origin. Found that 38% of NEOshave a meteoritic analogue; all C-types have a Carbonaceous Chondriteanalogue and 24% of S-types have an Ordinary Chondriteanalogue. A first conclusion is that NEOsare the principalparent bodies of meteorites that fall on the Earth. Most part of the investigated S-types NEOsdoes not fit with any meteorite: their spectra are typically redder

9 Study of space weathering The S-type NEOs that do not match with any meteorite are typically redder than the reddest OC meteorites and we conclude that this is due to space weathering effects Laboratory experiments made in collaboration with Catania observatory on OC meteorites indicate that ion bombardment of OC meteorites is able to mimic SW effects on S-type objects due to solar wind 7/9/2012 Italian Workshop on SSA

10 Peculiar objects: dead/dormant comets, family asteroids, rare taxonomic types We have found some peculiar objects: the spectra of four V-type objects very similar to Vesta. Then the spectrum of a NEO probably belonging to the rare R-class. The spectra of 2 objects of primitive composition that could be of cometaryorigin. In fact they also have a Tjtypically cometary and a high probability to come from the JFC channel.

11 Tools adopted for SINEO Observations: low resolution spectra in the spectral range micron Telescope used: ESO-NTT La Silla-Cile and TNG-La Palma-Canarias EMMI Gr#1, D=5.9 Å/pix, Slit=5, seeing=1 V=20 in T exp =1h S/N=20 DOLORES LR-R Grm3, D=2.9 Å/pix, Slit=5, seeing=1 V=20.0 in T exp =1.0h S/N=23 SOFI GB, D=6.9 Å/pix, Slit=2, seeing=1 NICS J=16 (V 17.5) in T exp =1.5h Amici, D= Å/pix, Slit=2, seeing=1 S/N=20 H=16.2 (V 18.0) in T exp =1.0h GR, D=10.2 Å/pix, Slit=2, seeing=1 S/N=30 S/N=20 K=16 (V 18) in T exp =2.5h web site:

12 Conclusion Need to extend the data base of Near Earth Objects spectra with long term dedicated observational campaigns to improve the knowledge of the composition of these objects. We need to make an inventory of the typical materials present among NEO population. This is an important information also for the mitigation, so for SSA. We need big telescopes as NEO are typically faint objects. The existence of a wide supported european and national program on SSA-NEO would give more strength to time request applications at the European and International Telescopes, typically subject to high pressure.

13 Principal References of the Team related to the subject MAGRIN S., LA FORGIA F.,, PAJOLA M., LAZZARIN M., MASSIRONI M., FERRI F., DA DEPPO V., BARBIERI C:, SIERKS H., OSIRIS Team (2012). (21) Lutetia spectrophotometry from Rosetta-OSIRIS images and comparison to ground-based observations. Planetary and Space Science, vol. 66, p BERTINI I., BARBIERI C., T.-M. HO, LAZZARIN M., CREMONESE G.,, KUPPERS M.,, MAGRIN S., MARCHI S. (2012). Photometric observations of comet 81P/Wild 2 during the 2010 perihelion passage. ASTRONOMY & ASTROPHYSICS, vol. 541 LAZZARIN M., MAGRIN S, MARCHI S, DOTTO E, PERNA D, BARBIERI C, BARUCCI M.A, FULCHIGNONI M (2010). Rotational variation of the spectral slope of (21) Lutetia, the second asteroid target of ESA Rosetta Mission.. MNRAS, vol. 408, p MARCHI, S, DELBO', M, MORBIDELLI, A, PAOLICCHI, P, LAZZARIN M., M (2009). Heating of near-earth objects and meteoroids due to close approaches to the Sun. MNRAS, vol. 400, p LAZZARIN M., S. MARCHI, L.V. MOROZ, S. MAGRIN (2009). New visible spectra and mineralogical assessment of (21) Lutetia, a target of the Rosetta Mission. Astronomy & Astrophysics, 498, 307 LAZZARIN M, MAGRIN, S, MARCHI, S (2008). SINEO: Spectroscopic Investigation of Near Earth Objects. In: Memorie della Societa Astronomica Italiana Supplement. Bormio, Gennaio 2008 Societa' Astronomica Italiana, vol. 12, p DE LUISE, F, PERNA, D, DOTTO, E, FORNASIER, S, BELSKAYA, I. N, BOATTINI, A, VALSECCHI, G. B, MILANI, A, ROSSI, A, LAZZARIN M., M, PAOLICCHI, P, FULCHIGNONI, M (2007). Physical investigation of the potentially hazardous Asteroid (144898) 2004 VD17. ICARUS, vol. 191; p MARCHI S, PAOLICCHI P, LAZZARIN M., MAGRIN S (2007). Space weathering of asteroids: similarities and discrepancies between Main Belt asteroids and NEOs. In: Near Earth Objects, our Celestial Neighbors: Opportunity and Risk, Proceedings if IAU Symposium 236. Edited by G.B. Valsecchi and D. Vokrouhlický ( 2007). Cambridge: Cambridge University Press, p MARCHI, S, PAOLICCHI, P, NESVORNY, D, MAGRIN, S, LAZZARIN, M. (2007). Space weathering and tidal effects among near-earth objects. In: Near Earth Objects, our Celestial Neighbors: Opportunity and Risk, Proceedings of IAU Symposium 236. Edited by G.B. Valsecchi and D. Vokrouhlický ( 2007). Cambridge: Cambridge University Press, p DE LUISE, F, PERNA, D, FORNASIER, S, DOTTO, E, MILANI, A, VALSECCHI, G. B, LAZZARIN M., M, BOATTINI, A, PAOLICCHI, P (2006). Unveiling The Nature Of 2004 VD17. In: Near Earth Objects, Our Celestial Neighbors: Opportunity and Risk, International Astronomical Union. Symposium no. 236, August, 2006 in Prague, Czech Republic. Prague, Czech Republic, 2006, vol. 236, p LAZZARIN M., MARCHI S, MOROZ L. V, BRUNETTO R, MAGRIN S, PAOLICCHI P, STRAZZULLA G (2006). Space Weathering in the Main Asteroid Belt: The Big Picture. The Astrophysical Journal, vol. 674; p MARCHI S, MAGRIN S, NESVORNY D, PAOLICCHI P, LAZZARIN M. (2006). A spectral slope versus perihelion distance correlation for planet-crossing asteroids. Montly Notices of The Royal Astronomical Society, vol. 368; p. L39-L42. MARCHI S., PAOLICCHI P., LAZZARIN M., MAGRIN S. (2006). A General Spectral Slope-Exposure Relation for S-Type Main Belt and Near-Earth Asteroids. The Astronomical Journal, vol. 131; p PAOLICCHI, P, LAZZARIN M., MARCHI, S, MAGRIN, S (2006). Space weathering of asteroids: similarities and discrepancies between Main Belt asteroids and NEOs. In: Near Earth Objects, Our Celestial Neighbors: Opportunity and Risk, International Astronomical Union. Symposium no. 236, held August, 2006 in Prague, Czech Republic. Prague, Czech Republic, August, 2006, vol. 236, p LAZZARIN M., MARCHI S., MAGRIN S., LICANDRO J. (2005). Spectroscopic Investigation of Near Earth Objects (SINEO) at Telscopio Nazionale Galileo. Montly Notices of the Royal Astronomical Society, vol. 359; p MAGRIN S., LAZZARIN M., MARCHI S. (2005). Spectrally Peculiar Objects from SINEO survey. In: American Astronomical Society, DPS meeting, vol. 37, p. 15 MARCHI S., BRUNETTO R., MAGRIN S., LAZZARIN M., GANDOLFI D. (2005). Space weathering of near-earth and main belt silicate-rich asteroids: observations and ion irradiation experiments. Astronomy & Astrophysics, vol. 443; p , ISSN: MARCHI S., LAZZARIN M., PAOLICCHI P., MAGRIN S. (2005). New V-type asteroids in near-earth space. ICARUS, vol. 175; p , ISSN: MARCHI S., PAOLICCHI P., LAZZARIN M., MAGRIN S. (2005). A Unique Spectral Slope-Exposure Relation for Silicate-Rich Main Belt and Near-Earth Asteroids. In: American Astronomical Society, DPS meeting, vol. 37, p. 15 LAZZARIN M., MARCHI S., BARUCCI M.A., DI MARTINO M., BARBIERI C. (2004). Visible and Near Infrared Spectroscopy of Near Earth Objects: First Results. ICARUS, vol. 169; p , ISSN:

14 Space Weathering:new and more general approach finding a general relation between the spectral slopes of silicate-rich asteroids and exposure to solar wind and micrometeorite impacts computed with the age and origin distance in the MB 559 S-type MBAs selected from SMASSII and 70 S-type NEOs from SMASS Near Earth Object Survey and from SINEO Exposure a 2 1 e T 2 1 T T = T MB MB coll = ( t ) T ( D ) = T, MB ( t t ) T ( D ) NEO NEO yark coll = NEO

15 SW:using a large data set of spectroscopic observations of planetcrossing asteroids (NEOs and Mars Crossers) we found a statistically significant correlation between their spectral slope and the perihelion distance. We find that Q and S-q type planet-crossing asteroids are more abundant (relative to more space weathered S-type objects) at small perihelion distances. Close encounters with terrestrial planets may produce tidal perturbations to their surfaces removing, also partially, old and weathered layers and expose non weathered OC-like material. 214 visible spectra of NEOs taken from SMASS-NEO and from SINEO and 70 MC from the SMASS II. Vertical lines are the perihelion, a and aphelion distances of the terrestrial planets.